The present invention relates generally to yarn carriers and, more particularly, to yarn winding tubes suitable for high speed winding operations.
For many years the textile industry has used winding operations to transfer yarn in packs from one processing operation to another. Yarn packs are formed by winding yarn onto carriers or winding tubes that are rotated at high speed, sometimes in excess of 6,000 RPM. The winding tubes, which are typically made of paperboard or plastic, are arranged consecutively so that the yarn can be transferred from one tube to the next without having to stop the winding process. To facilitate the winding process from one tube to the next, the tubes often define a start-up or pick-up groove in the body of the tube for capturing the yarn at the initial contact of the yarn and tube.
The lifespan of a conventional winding tube is limited, however, because the yarn wears down the start-up groove making it more difficult to capture yarn. Paperboard tubes are especially problematic, as moisture absorption by the paper tube may cause changes in dimension and other physical properties. Paper tubes also create paper dust and are more susceptible to being damaged. Plastic tubes have some improved wear characteristics over paper tubes, but plastic tubes are more costly to manufacture. Since tubes can be lost, damaged, or discarded after only a few uses, the cost of replacing plastic tubes may overshadow their longer lifespans compared to paper tubes.
The start-up groove of a conventional winding tube is typically formed by cutting or indenting the groove in the side of the tube body. However, some winding tubes incorporate an end ring on the end of the tube that forms a start-up groove with the tube body when the end ring is releasably secured thereto, such as by press fitting or by screwing a threaded end ring to the tube body. The start-up groove is defined by a scallop or indentation formed in the end ring and a shoulder defined by the tube when the end ring is secured to the tube. This design has an advantage over one-piece conventional tubes in that the end ring can be removed and replaced when the groove becomes worn by the yarn instead of replacing the entire winding tube. In addition, this design affords easier cleaning of the yarn that becomes trapped in the groove.
Thus, while removable end rings provide some advantages, further improvements can be made. In particular, conventional end rings are difficult to mount on the tube, as the indentation defined by the end ring typically extends a substantial portion, such as about 180xc2x0, around the end ring and thereby makes it difficult to accurately align the end ring against the tube. As such, the large indentation of the end ring can be inadvertently pressed against the tube, which xe2x80x9ctiltsxe2x80x9d or misaligns the remainder of the end ring.
One possible solution could be to reduce the size of the indentation defined by the end ring. However, providing a smaller indentation may make it more difficult for the yarn to catch in the groove, as the yarn must be positioned at the precise location of the groove as the tube revolves. Another possible solution could be to provide a threaded end ring that can be screwed onto an end of the tube. Threaded end rings are also problematic, however, as they are more difficult to manufacture. The threads are also susceptible to damage over time, which eventually leads to replacement of the entire tube.
An important feature in winding tubes is the means for identifying the particular type of yarn that is wound on the tube without requiring a detailed inspection of the yarn. One conventional method of identifying the yarn type includes marking the end of the winding tube with a colored marker or the like, or by placing a sticker or painting a symbol on the end of the tube. While these methods identify the yarn during a particular winding operation, the markings may not be applicable to future yarns, which limits the marked tubes to a particular type of yarn. Thus, tubes must be maintained in inventory for each type of yarn, which adds to the cost and complexity of the winding operation.
Thus, there is a need for a winding tube that has a long lifespan and is easy to assemble, yet that can also identify a variety of yarn types depending on the particular yarn used in the winding operation.
The present invention relates to a winding tube for use in winding yarn or fibers about the tube in a winding operation, wherein yarn or fibers are wound thereon and unwound therefrom. According to one embodiment of the present invention, the tube includes an end ring defining at least two recesses in an end face thereof that are spaced apart from each other so that the end ring can be secured and aligned with the body of the tube while providing at least two start-up grooves for capturing the yarn. In another embodiment, the end ring defines at least two more recesses defined by the opposite end face of the end ring such that the end ring is reversible, which makes mounting the end ring easier when preparing the tube for the winding process.
In particular, a tube for use in a textile winding operation according to one embodiment of the present invention includes a body having opposed ends and an outer surface extending therebetween. The body defines a generally radially extending shoulder proximate at least one end thereof, and in one embodiment defines a shoulder at each end of the tube. The body has a reduced diameter portion that extends from the end of the tube to the respective shoulder.
The tube also includes an end ring having opposing end faces and that is operable to releaseably engage the end of the body proximate the shoulder. The end ring can be formed from a variety of materials, such as polymers, paperboards, composites, resins, metals, and combinations thereof. The end ring has an inner diameter adapted to mate with the reduced diameter portion of the body and defines at least two recesses in at least one of the opposing end faces thereof. Advantageously, each of the recesses forms a start-up region with the shoulder for capturing yarn. In one embodiment, the end ring defines two recesses in one end face and two recesses on the opposite end face. The recesses on each end face are evenly spaced apart about the circumference of the end ring according to a preferred embodiment, such as by about 180 degrees if two recesses are provided on an end face, and the recesses in each end face are circumferentially offset from the recesses of the opposite end face, such as by about 90 degrees if two recesses are provided on each end face. In this regard, the end ring is reversible so that at least two start-up regions are provided for capturing yarn regardless of the mounting orientation of the end ring in relation to the body of the tube. In addition, when the body of the tube has a shoulder at each end, an end ring according to the present invention can be utilized at either or both ends of the tube so that either end of the tube can be used to initially capture yarn during the winding operation.
The recesses can have many shapes, and preferably have a curved shape. The recesses can also be symmetrical or asymmetrical in the circumferential direction. In one embodiment, the recesses have an asymmetrical ramp shape that provides one start-up region per recess. In this case, oppositely oriented ramp-shaped recesses can be positioned along the same side of the end ring such that the tube can be rotated in either direction and still capture yarn. Symmetrical recesses are also capable of capturing yarn regardless of the tube""s rotational direction.
The end ring also includes means for identifying the type of yarn to be captured during the winding operation. For example, in one embodiment the end ring is colored on at least a part of its surface to indicate a corresponding type of yarn. In this manner, the end ring can be removed and replaced on the body of the tube according to the type of yarn used in a particular winding process.
The winding tube of the present invention has a longer lifespan compared to conventional tubes, as the end rings can be replaced and/or discarded when they become worn instead of replacing the entire winding tube. In addition, the end ring of the present invention is easily aligned and secured to the body of the tube and defines recesses spaced along each end face of the end ring for forming start-up regions with the tube body. Furthermore, the end ring of the present invention can be selected so as to indicate what type of yarn is wound about the tube, which improves efficiency of the winding operation.